[zachrose]

I would happily carry a candy bar-sized object that connects wirelessly to the map app on my phone and haptically let's me know when it's pointed in the right direction. This would mean that: 1) A better compass can be used and 2) I don't have to look down at my phone.

[Nursie]

A candy-bar sized device with some sort of built-in vibration function?

You'd need a microcontroller and a bluetooth module, but I think I know where you can get a prototype. They usually have a grip-friendly and rain-protecting latex outer shell too...

[Terretta]

But then users would be constantly selecting "most turns" routes.

[zachrose]

Are you guys talking about dildos?

[Nursie]

Uh.... no? Why would we be talking about that? ;)

[greggman]

Your phone has vibration. Why not just just have the phone do the vibration you want?